Assembly for eliminating muzzle climb in automatic firearms



Jap.' 14, 1947. c. B. WILLIAMS 2,414,250

ASSEMBLY FOR ELIMINATING MUZZLE CLIMB IN AUTOMATIC FIREARMS www;

Jan. 14, 1947. C, B wlLLJAM, 2,414,250

ASSEMBLY FOR ELIMINATING MUZZLE CLIMB IN AUTOMATIC FIREARMS Filed Feb. 17, 1944 6 Sheets-Sheet 2 52 7073 v www Jan. 14, 1947. c. B. WILLIAMS 2,414,250

ASSEMBLY FOR ELIMINATING MUZZLE CLIMB IN AUTOMATIC FIREAHMS Filed Feb. 17, 1944 6 Sheets-Sheet 3 3o sa a: y 7 32 Jan. 14, 1947. c. B. WILLIAMS 2,414,250

ASSEMBLY r'un ELIMINATING MUZZLE CLIMB IN AUTOMATIC FIREARMS Flled Feb. 17, 1944 6 Sheets-Sheet 4 f2 5 36 4 ad B4 Ja..

l l 'l .90 ml 2f 4l I l uk m @3) i L @f 'l/llllIl//llllIllll/l Jan. 14, 1947. C, lB w|| |AMs 2,414,250

ASSEMBLY FOR ELIMINATING MUZZLE CLIMB IN AUTOMATIC FIREARMS Filed Feb. 17, V1.944 6 Sheets-Sheet 5 .1336 aid@ Jan. 14, 1947. c, wiLLlAMs 2,414,250

ASSEMBLY FCR ELIMINATING MUZZLE CLIMB IN AUTOMATIC FIREARMS Fild Feb.. 17, 1944 6 Sheets-Sheet 6 lill JZ 403 voc/who@ 406 414 y f2 32 404 /0/ 3* [lare/Me. #Wim/mr WMM@ Patented Jan. 14, 1947 ASSEMBLY FOR ELIMINATING MUZZLE CLIMB IN AUTOMATIC FIREARMS Clarence B. Williams, Grass Valley, Calif.

Application February 17, 1944, Serial No. 522.814

(Cl. i2-71) 6 Claims.

In automatic firearms, the rapid succession of discharges during full automatic fire produces a progression of power impulses or vibrations which cause the muzzle of the firearm to rise or climb in a manner which makes it impossible for the operator to hold the line of fire on the target. Prior to my inventionthe only procedure for satisfactorily overcoming this climbing tendency of the muzzle has been to limit full automatic fire of such firearms to bursts of three, four or five shots, the climb of the muzzle not being considered excessive during the firing of such short bursts. It is obvious, however, that the requirement for limiting full automatic fire to short bursts of shots results in a loss of much of the value of the full automatic fire cycle of automatic firearms.

' The purpose of my invention is to provide an assembly for suppressing muzzle climb during full automatic fire of automatic firearms to enable an operator to realize the full benet of the full automatic fire cycle of such firearms. My invention is particularly applicable to automatic firearms such as light machine guns known as. sub-machine guns, which are intended to be held by both hands of the operator and red either from the shoulder or from the hip. My invention is also applicable to other automatic firearms which are intended to be heldrby the operator with both hands and which have a fullautomatic fire cycle. The invention is not applicable to weapons such Ias automatic pistols, which are Y fired while being held with one hand.

Briefly; the invention involves a forearm grip assembly connected to the receiver of the nrearm independently of the barrel and which includes a compression spring member adapted, when compressed, toexert a forward force on the receiver of the firearm. The assembly is provided with friction producing means arranged to effect damping of the vibrations of the compression spring member during full automatic fire of theweapon.

For' a more complete understanding of my invention, reference is had to the accompanying drawings showing exemplary forms of my invention. `In the drawings:

Figure 1 is a side elevation view of a sub-machinefg'un with one form of my novel forearm grip assembly attached thereto;

FigureZ is a longitudinal sectional view of the forearm grip assembly shown in Figure 1;

Figure 3 is a transverse sectionall view looking in the direction of the arrows `along the line 3-3 of Figure 2;

Figure 4 is a side elevation view of a modied form of forearm grip assembly;

Figure 5 is a top plan view of the forearm grip assembly shown in Figure 4;

Figure 6 is a sectional view taken iri the direction of the arrows along the line-68 of Figure 5;

YFigure '7 is a transverse sectional view taken in the direction of the arrows along the line 1-1 of Figure 6;

Figures 8, 9, 10 and 11 are perspective views of the various elements of the friction producing means for damping vibrations of the compression spring members of the assemblies;

Figure 12 is a side elevation view of a third form of my invention;

Figure 13 lis a sectional view taken in the direction of the arrows along the line I 3-I3 of Figure 16';

Figure '14 is an end elevation view of arm grip assembly shown in Figure 12;

Figure 15 is a sectional view looking in the the 'foredirection of the arrows along theline I5-I5 of4 Figure 12;

Figure 16 isa top plan view of the forearm grip assembly shown in Figure 12;

Figure 17 is a bottom plan view of the assembly shown in Figure 12;

Figure 18 is a sectional view taken in the direction f the arrows along the line I8-I8 of Fisure 12;

Figure 19 is a side elevation viewrof a fourth form of my invention;

Figure 20 is a top plan view of the forearm grip assembly shown in Figure 19: and

Figure 21 isv a sectional view taken in the direction of the arrows along the line 2 I-2I of Fizure 19.

The sub-machine gun illustrated in Figure 1, as an example of one type of rearm with which my invention is usefu1is provided with a stock I, a receiver 2, a barrel 3 and a. rear grip 4. A

l forearm grip mounting 5 is rigidly secured to the receiver 2 and extends forwardly in a direction generally parallel to the barrel 3. The forearm grip assembly illustrated in Figures 1 to 3 is designated generally by the reference numeral 6 and is attached tol the free or forward end of the forearm griprmounting 5 in a manner more fully described hereinafter. Neither the y forearm grip -mounting E nor the forearm grip assembly 6 is attached to the barrel 3.

In Figures 2 and 3, an adapter block 'I is shown attached to the forwardend of the forearm grip mounting 5 by means of a cap screw 8. A block 9 is provided with upwardlyextending flanges I0 and II which lie on oppositfsldes of the mounting and the adapter block 1. and are secured to the latter by means of bolts I 2.

A longitudinal bore I3 extends through the block 9 with its axis generally parallel to the mounting 5. Outer tube I4 is received within the bore I3 and is reciprocable therein relative to the block 9. An inner tube I5 is telescoped in the outer tube I4. Flanged end plates I 6 and I'I are positioned respectively at the forward and rear ends of the inner tube I5. These end plates serve to position a hollow hand grip piece I8 about the telescoping tubes I4 and I5 in a manner most clearly illustrated in Figure 2. 'I'he end plates I6 and II are retained in position on the ends of the tube I5 by means of pins I9.

A compressible coil spring member 2|) surrounds the tube I4 and is positioned between the rear face of the front end plate I6 and the forward face of the block 9; A bushing 2| also surrounds the tube I4 and abuts against the rear face of the block 9. The bushing 2| is annular in form and at its rear end is provided with an inwardly tapering face 22. A split friction ring 23 (see Figure 9) surrounds the tube I4 immediately to the rear of the bushing 2|. The friction ring 23 is preferably constructed of bronze and is provided with a tapered face 24 at its forward end and a similarly tapered face 25 at its rear end. As best seen in Figure 2, the tapered face 24 at the forward end of the friction ring 23 is of a configuration to fit snugly against the tapered rear face 22 of the vbushing 2|. A spring steel clip 26 (see Figure 10) partially encirclcs the friction ring 23 and urges the surface of the bore through the split friction ring into contact with the outer surface of the tube I4. A second bushing 2'I surrounds the tube I4 and lies immediately to the rear of the friction ring 23. The bushing 21 (see Figure 1l) is provided at its forward end with a tapered face 28 which fits snugly against the .tapered face 25 of the friction ring 23. A compressible coil spring 29 surrounds the tube I4 and lies between the forward face of the end plate Il and the rear face of the bushing 2I. It will be noted from Figure 2 that the spring The operator grasps the rear grip 4 in one hand and the forearm grip piece I8 of the forearm grip assembly 6 in the other` hand and appropriately positions the firearm either at the shoulder or the hip, according to the preferred mode of ring. The operator then simultaneously pushes forwardly with the hand engaging the forearm grip piece I8 and pulls rearwardly with the hand grasping the rear grip 4. The weapon may then be iired at full automatic fire and it will be found that the tendency of the muzzle to rise or climb is eliminated or suppressed to an extent which enables the operator to easily hold the target within the line of fire.

I do not desire to limit my invention to any particular theory of operation or explanation of member 29 is of substantially greater length than the spring member 2|).

The hand grip piece I8 is provided with an upper opening 3|) which is elongated to permit longitudinal movement of the hand grip piece relative to the block 9 and its flangesIII and II. I have found it advisable to provide a cover tube 3| to assist in protecting the tubes, the bushing and the frictionring from matter.

Figures 1 and 2 illustrate the positions of the various elements of the'forearm grip assembly which those elements occupy when the Weapon is not in use. Under these circumstances, the stresses in the spring members 20 and 29, which are relatively light due to the fact that these spring members are only slightly compressed; balance each other and the block 9 assumes what dust or other foreign -might be termed the neutral position shown in Figure 2. When the various elements occupy the position shown in Figure 2. the friction ring 23 grips the outer surface of the tube I4 very lightly and this gripping action is only sufficient to present a slight frictional resistance to movement of the tube I4 relative to the ring 23. I will now describe the use of my forearm grip assembly for its intended purpose, that is thel suppression of a rising motion of the muzzle of the firearm.

the principles involved, but it is appropriate to describe briefly the functions which the various elements appear to perform when the assembly is manipulated in the manner described above. Since the'rear grip 4 and the forearm grip mounting 5 are both rigidly attached to the receiver 2, it is apparent that when the forearm grip piece I8 is moved forwardly there must be a forward displacement of the tubes I4 and I5 relative to the block 9. This displacement causes an increase in the compression of the spring member 29. Due to the increase in compression of the spring member 29, the tapered face 28 of the bushing 2l coacts with the tapered rear face of the friction ring 23 with a resulting increase in the frictional gripping action of the ring 23 on the tube I4. At the same time, the tapered rear face 22 of the bushing 2| coacts with the tapered face 24 of the friction ring 23 and likewise urges the ring 23 into more' intimate frictional engagement with the outer surface of the tube I4. Recoil shocks to which the receiver 2 is subjected are transmitted to the block 9 through the mounting 5 and the adapter block 'I but any tendency of the block 9 to partake of recoil movement is resisted by resilient action of the spring member 29. Friction between the friction ring 23 and the tube I4 appears to be effective to eliminate any possibility of the spring member 29 vibrating excessively. In other words, the friction ring 23 appears to effect a damping action on vibrations of the lspring 29' without. however. interfering with the ability of the spring member to absorb recoil shocks and to thus suppress the climbing tendency oi the muzzle of the weapon. When the forearm grip piece I8 is released by the operator, the elements, of course. assume the neutral positions shown in Figure 2.

The form of the invention described above in connection with Figures 1 to 3 of the drawings is probably the most simple of the illustrated forms and. for that reason. it well serves the purpose of illustrating the general principles involved in my invention. However, some operators consider that the necessity of pushing forwardly with the hand engaging the forearm grip assembly results in an awkward or unnatural feeling while using the yweapon and for that reason I prefer to'provide additional forms of my invention in which it is unnecessary for the operator to push forwardly on the forearm grip assembly. One such form of the invention is shown in Figures 4 to 7, inclusive. Referring rst to Figure 6.

the reference numeral 32 designates a. block pro-y atie-,ato

the axis of which extends generally parallel to the mounting 6 and positioned within the bore 31 is a cover tube 88. A bushing 39 lies within the cover tube 38 and surrounds an elongated tube 40, each end of which extends well beyond the block 32. The tube 40 is provided at one end thereof with an outwardly extending annular ange 4I and is threaded at the opposite end for reception of a threaded retainer ring 42. A rectangular box-like frame structure having end plates 43 and 44 and side plates 45 and 46 is supported by the tube 48 in the manner best shown in Figure 6 and is retained thereon by means of the flange 4I and the retainer ring 42.

A compressible coil spring member 41 surrounds the tube 49 and lies between the rear face of the end plate 43 and the forward face or end of the bushing 39. The rear end of the bushing 39 is provided with an inwardly tapering face 48. This bushing is. best shown in Figure 8 of thedrawings. This form of the invention is also provided with a friction ring, a spring clip and a rear bushing and since these parts are all identical with the corresponding parts inthe form of the invention shown in Figures 1 to 3, they are designated by the same reference numerals. A compressible coil spring member 49 also surrounds the tube 48 and lies to the rear of the rear end of the bushing 21. compressing member 5U surrounds the spring member 49 and is arranged to telescope over the cover tube 38. The spring compressing member 56 is provided with an inwardly extending flange 5| which abuts against the rear end of the spring member 49. The inwardly extending flange 5| may be made integral with the member 50 or it may be' secured thereto in any convenient manner.

The spring compressing member 50 is provided with a pair of oppositely disposed laterally extending bosses 52 and 59, which extend through elongated slots 54 and 55 in the side plates 45 and 46 respectively. In this form of the invention, a lever and mechanical linkage arrangement are provided for cooperating with the bosses 62 and 53 for moving the spring compressing member 50 forwardly. -A lever 56 is journaled on a shaft 51 which is supported in openings in the side plates 45 and 46. The lever 66'is movable from the full line position in Figure 4 to the broken line position and in the latter position the lever is partially received in a groove 58 of a pistol grip 59. which is rigidly secured to the side plates 46 and 48.

A shaft 68 extends through the lever 56 in a position slightly spaced toward the free'end of the lever from the shaft 51. On the ends of the shaft 60 are links 6l and 62'which lie just inside the side plates 45 and 46 respectively. The upper end of the linkV 6I is provided with an outwardly extending boss 63 which extends through an arcuate groove 64 in the side plate 45 and the link 62 is similarly provided with an outwardly extending boss 65 lying inan arcuate slot in the side plate 46. A triangular shaped link 66 is pivoted on the side plate 45 at 61 and a similartri- ,angular shaped link 68 is pivoted on the side plate 46 at 69. The forward ends of the triangular shaped links 66 and 68 are journaled on the bosses 63 and 65 respectively. A link 10 has one end pivotally connected to the triangular shaped link 66 while its opposite end is pivotally connected at 1I to the upper end of a slotted link 12, the lower end of which is pivoted to the side plate 46 at 13. Similarly, the rear end of the triangular A tubular spring Y 6 shaped link 68 has pivotally connected thereto a link 14 which in turn is pivotally connected to a slotted link 16 pivoted to the side plate 46. The slotted links 12 and 15 are respectively provided with elongated slots 16 and 11 for receiving the bosses 52 and 53 on the spring compressing member 50.

From the foregoing description it will be apparent that movement of the lever 56 from the full line position shown in Figure 4 to the broken line position will eect a forward movement of the spring compressing member 50. This forward movement of the spring compressing member 50 results in compression of the spring members 41 and 49 and it also causes an increase in the frictional gripping action of .the friction ring 23 on the tube 40 in the same manner as described above in connection with the description of the form of the inven'tion shown in Figures l to 3. The general principle of operation of this form of the invention is identical with the principle of operation of the form shown in Figures l to 3, but it will be noted that in this form of the invention it is unnecessary Vfor the operator to exert a forward push on the forearm grip assembly.

The formof the invention illustrated in Figures 12 to 18 permits the operator to render the forearm grip assembly operative for its intended purpose by exerting a backward pull on the forearm grip. In this form of the invention, the block, tube, spring members, friction ring, bushings and spring compressing member are identical with those described in connection with the description .of the form of the invention shown in Figures 4 to '7, and are consequently designated by like reference numerals. The end plates 43 and 44 may also be identical with the end plates described above, but the side plates 18 and 19 of the frame structure necessarily differs somewhat from the side plates 45 and 46. The bosses 52 and 53 on the spring compressing member 5D extend through slots in the side plates 18 and 19 respectively. A slotted link 8i is pivoted to the side plate 18 at 82 and is provided with a slot 83 for receiving the boss 52. LA link 84 is pivoted at 85 to one end of the slotted link 8l while the opposite end of this link 84 is pivoted at 86 to a triangular shaped link 81. The triangular shaped link 81 is pivoted to the side plate 18 at 88. A link 89 is pivotally connected to the triangular shaped link 81 at 90. The side plate 19 is provided with similar slots and links and the corresponding parts are designated by the same reference numerals. A generally U.shaped member, which is designated by the reference'numerul 9| and which is preferably constructed of wood, encloses the lower portion of the assembly and is secured to the end plates 43 and 44 by mea-ns of screws 92. As is clearly shown in Figure 15,

the sides 94 of the member 9| provide adequate` clearance for the linkage mechanism assembledr on the side plates 18 and7 19. VIdentical metal strips' 95 are secured to opposite sides of the memberl'9l in positions most clearly shown in Figures 14 and 15.. The strips 95 serve as guides for a hand grip piece 96 which is reciprocable with respect to the member 9| and is provided with grooves 91 for receiving the strips 95.

Attached to the forward portion of the handl grip piece 96 by means of screws 98 is a metal bearing member 99 and passing through this bearing member is a shaft |98 which is connected to-the lower ends of the links 89. Referring now to Figure 13, it will be apparent that when the hand grip piece 96 is moved from the position in which it is shown in full line to the position shown in broken line, the various links will also move from their full line positions to their broken line positions with a resulting forward movement of the bosses 52 and 53 and also of the spring compressing member 50. This rcsults in compression of the spring members 41 and 49 and causes the friction ring 23 to frictionally grip the outer surface of the tube 40 in the manner which has beendescribed above.

When this form of the invention is attached to a weapon such as that shown in Figure 1, the operator merely grasps the hand grip piece96 and pulls backwardly thereon to suppress the rising or climbing tendency of the muzzle ofV the weapon.

The form of the invention shown in Figures 19 to 21 operates in somewhat the same manner as the form disclosed in Figures 4 to 7. Many of the elements in this form of the invention are identical with those described above and are designated by the same reference numerals, The side plates |01 .and |02 are provided with horizontally extending rear slots |03 for the bosses 52 and 53 on the spring compressing member 50. A rack plate |04 is provided on each side plate and receives the projecting ends of the bosses 52 and 53. The side plates ||1and |02 are also provided with forward horizontally extending slots |05 and the forward ends of the rack pla-te |04 are provided with inwardly extending stub projections |06 which are received in the slots |05. By this arrangement the rack plates |04 are movable longitudinally with respect to the side plates |0| and |02 and the spring compressing member 50 will be caused to move with the rack plates by virtue of their connections through the bosses 52 and 53. rA shaft |01 is mounted in bearings |08 and |09 on the side plates |0| and |02 respectively and keyed to this shaft by a key H0 is a lever IH Vsegmental gear members H2 and H3 are keyed to the ends of the shaft |01 and lie outside the side plates |0| and |02 re-y spectively. The segmental gear members I2 and H3 are provided with gear teeth H4 which cooperate with gear teeth H5 on the rack plates |04. A pistol grip 6` is attached to the side plates |0| and |02 inthe position clearly shown in Figure 19.

InFigures 19 to 21, this form of the invention is illustrated in itsv operative position, that is with the spring members41 and 49 compressed. When this assembly is attached to a firearm such .as that illustrated in Figure 1, the operator merely graspsthe pistol grip ||6^ and the lever and draws the lever IH toward the pistol grip so that it occupies the position shown in Figure 19. The weapon may then be fired at full i automatic fire and the tendency of the muzzle of the weapon to climb will be suppressed to the `extent that the target may be held in the line vof lire.

The several forms of my invention which I have illustrated andldescrlbed are exemplary only. It

will be obvious that various modifications may be v4resorted to without sacrificing the advantages of my invention. y Having thus described my invention, I claim:

d 1 .A forearm grip assembly for 4suppressing the tendency of the muzzle of an automatic firearm to climb during automatic firing comprising a forearm grip mounting having one end secured to .the receiver of the firearm and extending forwardly in a direction generally parallel to the barrel of the firearm, a block carried by the forward end of said mounting and having a bore therethrough with the axis of the bore generally parallel to the barrel of the firearm, an' elongated member extending through and reciprocable in said bore, a compression spring member surrounding said elongated member to the rear of said block, a manually operable forearm grip connected to said elongated member for engaging the rear end of said spring member and compressing said spring member toward said block whereby rearward movement of said block relative to said elongated member is opposed by compressive stresses in said spring member, and means adjacent said block for providing frictional resistance to reciprocation of said block relative to said elongated member.

2. A forearm grip assembly for suppressing the tendency of the muzzle of an automatic firearm to climb during automatic firing comprising a forearm grip mounting having one end secured to the receiver of the firearm and extending forwardly in a direction generally parallel to the barrel of the firearm, a block secured tothe forward end of said mounting and having a bore therethrough with the axis of the bore generally parallel to the barrel of the firearm, an elongated member extending through and reciprocable in said bore, a front compression spring member surrounding said elongatedimember in advance of said block, a rear compression spring member surrounding said elongated member to the rear of said block, a forearm grip piece connected to saidlelongated member and including means for engaging and compressing the remote ends of said Ispring members toward said block whereby movement of said block relative to said elongated member is opposed by balanced compressive stresses` in said front and rear spring members, and means adjacent said block for pro- Viding frictional resistance to reciprocation of said block relative to said elongated member.

3. A forearm grip assembly for suppressing 'the tendency of the muzzle of an automatic firearm to climb during automatic firing comprising a forearm grip mounting having one end rigidly secured to the receiver of the firearm and extending forwardly in a direction generally parallel to the barrel of the firearm, a block secured to the forward end of said mounting andhaving a bore therethrough with the axis of the bore generally parallel to the barrel of the rearm, an elongated member extending through and reciprocable in said bore, a compression coil spring member surrounding said elongated member and disposed to the rear of said block, compressing means on said elongated member engaging the rear end of said spring member, friction means on said elongated member between said s pring member andsaid block for providing frictional resistance to movement of said block relative to said elongated memberv upon compression of said spring member, and a forearm grip having manually operable means for moving said compressing means forwardly to effect compression of said spring member,

4. A forearm grip assembly for suppressing the tendency of the muzzle of an automatic firearm to climb during automatic firing comprising a forearm grip mounting having one end secured wardly in a direction generally parallel to the barrel of the firearm, a block secured to the forward end of said mounting and having a bore therethrough with the axis of the bore generally parallel to the barrel of the firearm. an elongated member extending through and reciprocable in said bore, a compression spring member surrounding said elongated member and disposed to -the rear of said block, compressing means on said elongated member engaging the rear end A,of said spring member, means adjacent said block'for providinglfrictional resistance to movement Aof said block relative to said elongated`member upon compression of said spring member against said block, and a forearm `grip having means for inanuallyA moving said compressing meansforvvardly to. effect compression of' said spring member against said block. i

5. A forearm grip assembly for suppressing the Y' tendency of the muzzle of Ian automatic `firearm to climb during automatic firing comprisinga block attached to the receiver of the rearmbiit free `from attachment to the lbarrel ofthe firearm, said block having a bore extendingf therethrough in a direction generally parallel to the barrel -of the firearm; an elongated member extending through and reciprocable in said bore, a compression spring member surrounding -said elongated member and disposed to therear of said block, a manually operable forearm gripy mechanism mounted against longitudinal movement on said elongated member and including means for engaging and compressing said spring member toward said block whereby rearward movement of said block relative to said elongated member is opposed by compressive stresses in said spring member, and friction means interposed between said block and the forward end of said` spring member for providing frictional resistance to reciprocation of said block relative to said elongated member..

6. A forearmgrip assembly for suppressing the tendency of the muzzle of an automatic firearm ,to climb during automatic-firing, comprising a block secured to the receiver of the rearm, said block having a boretherethrough with the axis of the bore generally parallel to the barrel of the firearm, an yelongated-member extending through and reciprocable in said bore, a front compression spring member surrounding said elongated member forwardly of said block, a rear compression spring member surrounding said.A elongated member rearwardly of said block, a forearm grip connected'to said elongated member, means associated with said forearm grip for engaging the remote ends of said fro'nt and rear spring` members andcompressing said spring members to- 'ward said block whereby longitudinal movement of said block-relative to said elongated member is opposed by balanced compressive stresses in said front -and rear spring members, and friction means on said elongated member between said block and the forward end of said rear spring member arranged to provide frictional resistance to longitudinal movement of said block, relative to said elongated member.

CLARENCE B. 

